Graphite intercalation

ABSTRACT

Intercalation of a Lewis acid fluoride in graphite is effected in the presence of gaseous fluorine. The reaction results in new compositions useful as catalysts and as atmospheric pressure containers for normally gaseous Lewis acid fluorides.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the intercalation of a Lewis acid fluoride ingraphite giving rise to products useful in catalysis and as atmosphericpressure storage for normally gaseous Lewis acid fluorides.

2. Description of the Prior Art

The intercalation of various salts in the lattice of graphite haspreviously been described. Thus, it has been reported in J. Chem. Soc.,Chem. Comm., 21, 815 (1973) that while there have been few instances ofintercalation of fluorides in graphite, the intercalation of antimonypentafluoride in the lattice of graphite is accomplished by heating amixture of SbF₅ and graphite at 110°C for a few days. It has also beenknown to accomplish the conversion of hydrocarbons in the presence of awide variety of catalysts including those in which the active catalyticcomponent is deposited on a porous inert support such as, for example,graphite. U.S. Pat. No. 3,678,120 describes such process in which thecatalyst employed is a porous inert solid support having depositedthereon a catalytic complex of an antimony pentafluoride component and ahydrogen fluoride or a fluorosulfonic acid component. It has beenreported in U.S. Pat. No. 3,708,553 that hydrocarbon conversion and morespecifically alkylation can be carried out in the presence of a Lewisacid such as antimony pentafluoride combined with a Bronsted acid suchas fluorosulfuric acid. In none of this prior art, which is the mostrelevant known, is there any recognition or disclosure of intercalatinga Lewis acid fluoride in graphite in the presence of gaseous fluorine,nor is there any disclosure of intercalates of boron trifluoride orphosphorus pentafluoride with the graphite.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a method formanufacturing intercalates of a Lewis acid fluoride with graphite notheretofore available. Such method entails effecting intercalation in thepresence of fluorine which appears to act as a catalyst for the reactionand is not retained in the graphite structure.

It has been found that the new method affords means for the productionof novel compositions of certain Lewis acids, notably boron trifluorideand phosphorus pentafluoride, which have not previously been capable ofintercalation in graphite.

Thus, it has been observed that when BF₃ or PF₅ are streamed through abed of graphite, no intercalation occurs. Similarly, when fluorine,diluted with nitrogen to yield a mixture of 10 volume percent fluorineis streamed through a bed of graphite, no intercalation occurs. However,when the above Lewis acid fluorides are costreamed with fluorine dilutedwith nitrogen to the indicated concentration, rapid intercalation of theLewis acid fluoride occurs.

The present process comprises contact of graphite with a Lewis acidfluoride, having a boiling point below about 300°C and preferably belowabout 150°C, in the presence of fluorine at a temperature within theapproximate range of -20°C to 300°C for at least a period of time toeffect a weight increase in the graphite. Generally, the reaction iscarried out at approximately atmospheric pressure, although the pressuremay be within the range of about .1 to about 10 atmospheres. Thereaction temperature desirably is between about 15°C and about 150°C andpreferably between about 20°C and about 40°C. The time of contact issuch as to introduce the desired amount of Lewis acid fluoride into thegraphite and generally is between about 1/4 and about 24 hours and moreusually between about 1 and about 10 hours.

It is essential in accordance with the present method that contact ofthe graphite and Lewis acid fluoride takes place in the presence offluorine. Individual streams of the Lewis acid fluoride and fluorine maybe simultaneously brought into contact with the graphite under the aboveconditions. A particularly feasible means for contacting the reactantsinvolves prior admixing of the Lewis acid fluoride and fluorine andthereafter contacting the graphite with such mixed stream. The relativeamounts of Lewis acid fluoride and fluorine employed, on a weight basisare generally between about 30:1 and about 2:1. Fluorine may be used inundiluted form, but it is generally preferred to dilute the fluorinewith an inert gas, e.g. nitrogen, helium or argon, such that thefluorine stream contains, on a volume basis, between about 1 and about50 percent fluorine.

After completion of the reaction, an inert gas such as nitrogen, heliumor argon is desirably passed through the bed of graphite containingintercalated Lewis acid fluoride at a sufficient rate and for asufficient time to sweep fluorine and any non-intercalated Lewis acidfluoride from the pores of the graphite. The intercalated product soobtained generally contains between about 5 and about 50 weight percentand preferably between about 10 and about 40 weight percent of Lewisacid fluoride. The density of the intercalate is substantially less thanthat of the starting graphite, attributable to a considerable degree ofexpansion in the final product.

The Lewis acid fluoride intercalated in graphite in accordance with thepresent invention is generally one having the formula MX_(n) where M isan element selected from Group II, IIIA, IV, V or VI-B of the PeriodidTable, X is fluorine or fluorine in combination with oxygen and n is aninteger of from 2 to 5. Representative of such compounds are vanadiumpentafluoride, boron trifluoride, niobium pentafluoride, tantalumpentafluoride, silicon tetrafluoride, germanium tetrafluoride, seleniumtetrafluoride, antimony pentafluoride, tellurium tetrafluoride, sulfurtetrafluoride, bismuth pentafluoride, molybdenum pentafluoride, iodinepentafluoride, bromine pentafluoride, phosphorus pentafluoride, andarsenic pentafluoride. In addition to the fluorides, oxyfluorides of thetransition metals, e.g. chromium oxyfluoride, are particularly preferredembodiments of the latter type compounds. The Lewis acid fluorides,characterized by a boiling point below about 300°C and preferably belowabout 150°C, may be employed as such or generated in situ by thereaction of any salt capable of being oxidized by fluorine to fluorides.Thus, it is contemplated that a salt of a metal, which forms a Lewisacid fluoride boiling below about 300°C, such as a suitable metalchloride, bromide or iodide, may be initially used in the intercalationreaction conducted, in accordance with the present invention, in thepresence of fluorine and during such reaction the Lewis acid fluoridewill be formed in situ by reason of the interaction of such salt, e.g.chloride, bromide or iodide and fluorine.

Intercalation of some of these Lewis acid fluorides with graphite, e.g.antimony pentafluoride, has previously been achieved utilizing a methodother than that described herein. Other of the Lewis acids, e.g. borontrifluoride and phosphorus pentafluoride, have not been capable ofproduction by previously known techniques and are considered to be newcompositions useful as catalysts in conversion of organic compoundsincluding, by way of example, isomerization, polymerization, crackingand alkylation.

In one embodiment of the invention, the graphite/intercalated Lewis acidcomposite catalyst may additionally have intercalated in the graphite aBronsted acid such as hydrofluoric acid, hydrochloric acid,fluorosulfuric acid or trifluoromethane-sulfonic acid and mixturesthereof. In another embodiment of the invention, thegraphite/intercalated Lewis acid fluoride composite may have a GroupVI-B or Group VIII metal additionally intercalated in the graphite toprovide a highly effective catalyst.

The graphite utilized in the present invention is desirablycharacterized by a surface area of about 0.3 to about 50 m² /gram; atypical graphite applicable for use in the present invention ischaracterized by the following properties:

Surface Area of 0.46 m² /gram

Real Density of 2.16 gram/cc

Particle Density of 1.90 gram/cc

Pore Volume of 0.065 cc/gram

When a Bronsted acid, such as hydrofluoric acid, hydrochloric acid,fluorosulfuric acid or trifluoromethanesulfonic acid is alsointercalated in the graphite lattice, the amount thereof is generallybetween about 0.5 and about 75 weight percent and preferably betweenabout 1 and about 50 weight percent, with the molar ratio of Bronsted toLewis acid fluoride being within the range of .1:1 to 50:1 and moreparticularly in the range of 1:1 to 5:1.

When a Group VI-B or Group VIII metal is additionally intercalated inthe graphite, the amount employed is such as to afford a resultingcomposite containing between about 0.1 and about 20 weight percent ofthe metal. With metals of the platinum group, the amount of metal ispreferably in the approximate range of 0.1 and 5 weight percent. Othermetals contemplated for intercalation include nickel, cobalt, ironchromium, molybdenum and tungsten. Particularly preferred are the GroupVIII metals, especially platinum and palladium.

When a metal of Group VI-B or Group VIII is also desired in thecatalyst, intercalation is achieved by heating a compound of theappropriate metal with graphite, preferably in the presence of chlorine,at a temperature within the approximate range of 100° to 200°C for aperiod of between about 4 and about 24 hours. The intercalated metalcompound is then reduced, generally with flowing hydrogen, at atemperature of about 300° to about 400°C for a period of approximately 8to 24 hours. Thereafter, intercalation of the desired Lewis acidfluoride into the metal/intercalated graphite composite may be effectedas described above.

In similar fashion, when a Bronsted acid is additionally desired in thecatalyst, such acid may be intercalated after intercalation of the Lewisacid fluoride into the lattice of the graphite. Intercalation of theBronsted acid is achieved by heating the graphite with such acid at atemperature between about -40°C and about 100°C for a period of betweenabout 1 and about 5 hours. It is also feasible and, in some instancespreferable, to intercalate both (1) a metal of Group VI-B or Group VIIIand (2) a Bronsted acid into the lattice of the graphite having Lewisacid fluoride under the conditions specified hereinabove, and thenintercalation of the Bronsted acid as described.

A wide variety of hydrocarbon conversion reactions may be effectedutilizing the present catalyst. Such conversion processes include thosecatalyzed by the presence of acidic sites such as cracking,isomerization, alkylation, polymerization, disproportionation,dealkylation, transalkylation and similar related processes. Theseprocesses are effected by contacting a hydrocarbon or hydrocarbonmixture with the above-described catalyst at hydrocarbon conversionconditions. The catalyst to hydrocarbon weight ratio employed isgenerally between about 1:5 and about 1:20. The temperature employed isgenerally between about 0°C and about 650°C. Contact between thecatalyst and hydrocarbon charge may take place utilizing any of theconventional systems such as a fixed bed system, a moving bed system, afluidized bed system or a continuous or batch-type operation. Thehydrocarbon conversion utilizing the present catalyst may be carried outas either a vapor phase, a liquid phase or a mixed phase operation.Conversion may take place in the absence or presence of hydrogen.Operation in the presence of hydrogen is particularly advantageous forisomerization in preserving catalyst life.

Isomerization of isomerizable hydrocarbons, such as naphthenes and/orparaffins, may be effectively carried out utilizing the catalyst of thisinvention. Thus, isomerization of straight chain or slightly branchedchain paraffins containing 4 or more carbon atoms per molecule, such asnormal butane, normal pentane, normal hexane, normal heptane, and normaloctane may be readily effected. Likewise, cycloparaffins containing atleast 5 carbon atoms in the ring, such as alkyl cyclopentanes andcyclohexanes may be effectively isomerized utilizing the presentcatalyst. It is contemplated that straight or branched chain saturatedhydrocarbons containing up to 30 carbon atoms or more per molecule maybe isomerized with the present catalyst, regardless of the source ofsuch hydrocarbons or mixtures containing the same. As examples ofcommercial mixtures, mention can be made of straight-run tops or lightnaphtha fractions which in various refineries are available in largeamounts.

In carrying out isomerization of isomerizable hydrocarbons utilizing thepresent catalyst, contact between the catalyst and hydrocarbon charge isconducted at a temperature between about 0°C and about 200°C andpreferably between about 30°C and about 150°C at a pressure betweenabout atmospheric and about 30 atmospheres or more. The hydrocarboncharge is passed over the catalyst at a liquid hourly space velocitygenerally between about 0.2 and about 10 and preferably between about0.5 and about 4. The resulting product is withdrawn from the reactionzone, separated from the reactor effluent and recovered by any suitablemeans such as fractional distillation. Any unreacted starting materialmay be recycled to form a portion of the feedstock.

The catalyst of this invention is also suitable for catalyzinghydrocarbon cracking. The hydrocarbon charge in such process maycomprise one or more normal paraffins or may be a complex mixture ofparaffins, naphthenes and aromatics, such as occurs in petroleum gasoil, which is the feedstock normally conducted to a commercial catalyticcracking unit. Hydrocarbon cracking utilizing the catalyst of thisinvention is essentially conducted at a temperature between about 400°Cand 650°C, a pressure of from about atmospheric to about 5 atmospheresand employing a liquid hourly space velocity of between about 0.5 andabout 100.

Alkylation employing the catalyst described herein may also beeffectively carried out. Thus, alkylation of an alkylatable hydrocarbonwith an olefin, alkyl halide or alcohol is desirably effected in thepresence of the catalyst of this invention at alkylation conditionsincluding a temperature of about 0°C to about 150°C and a pressure ofbetween about atmospheric and about 500 psig. The mole ratio ofalkylatable hydrocarbon to alkylating agent is preferably between about1:1 to about 10:1.

Polymerization of polymerizable organic compounds, such as olefins andtetrahydrofuran may be effectively conducted in the presence of thecatalysts described herein. Such polymerization is suitably effected ata temperature between about -20°C and about 100°C and preferably betweenabout 0°C and about 50°C at a pressure between about atmospheric andabout 10 atmospheres utilizing a batch or container operation. Thecharge is passed over the catalyst at a liquid hourly space velocitygenerally between about 0.5 and about 1000 and preferably between about1 and about 200.

In addition to use as catalysts, the intercalates of the lower boilingLewis acid fluorides with graphite afford atmospheric pressure storagefor the normally gaseous Lewis acid fluorides. It is contemplated thatLewis acid fluorides having a boiling point less than about 50°C may beemployed for such purpose. Thus, although both BF₃ and PF₅ are lowboiling compounds, having boiling points of -99°C and -75°Crespectively, the graphite intercalates have been observed to degasquite slowly at ambient temperature. Thermogravimetric analysis hasshown that gas evolution becomes rapid at 100°-200°C. These intercalatesare thus useful as atmospheric pressure containers for BF₃ or PF₅. Theneed for high pressure equipment is obviated. A known amount of gascould be generated by heating the corresponding weight of intercalate.For example, heating 10 grams BF₃ /graphite intercalate (21.2 weightpercent BF₃) to 150°C would generate 2.12 grams or 700 cc of BF₃.

DESCRIPTION OF SPECIFIC EMBODIMENTS

The following examples will serve to illustrate the invention withoutlimiting the same:

EXAMPLE 1

Intercalation of BF₃ in graphite was accomplished by costreaming BF₃ and10 weight percent fluorine in nitrogen each at 40 cc/minute through a 10gram bed of graphite.

The bed temperature increased rapidly from 22°C to 34°C and thengradually decreased to 24°C over a 90 minute contact time. Dry nitrogenwas then passed through the bed for 30 minutes at 80 cc/minute. No BF₃fumes were evident in the off gas.

The weight increase of the graphite was 1.91 grams, corresponding to a16 weight percent BF₃ loading. The density of the graphite decreasedfrom 0.845 gram/cc to 0.573 gram/cc, corresponding to a 76 percentvolume expansion. X-ray diffraction analysis indicated that theintercalate is third stage (every third layer occupied by BF₃) and thatthe layer spacing for graphite increased from 3.35A. to 7.60A. Theelemental analysis in weight percent was

              Theory       Observed                                               ______________________________________                                        B           2.58           2.56                                               E           13.62          13.06                                              ______________________________________                                    

EXAMPLE 2

Intercalation of PF₅ in graphite was accomplished by costreaming PF₅ and10 volume percent of fluorine in nitrogen each at 40 cc/minute through a15 gram bed of graphite.

The bed temperature increased rapidly from 23°C to 39°C and thengradually dropped to 24°C over a 120 minute contact time. Dry nitrogenwas then passed up through the bed for 25 minutes at 80 cc/minute. NoPF₅ fumes were evident in the off gas.

The weight increase of the graphite was 5.37 grams, corresponding to a26.4 weight percent PF₅ loading. The density of the graphite decreasedfrom 0.845 gram/cc to 0.57 gram/cc, corresponding to a 101% by volumeexpansion. X-ray diffraction analysis indicated that the PF₅ intercalateis third stage (every third layer occupied by PF₅) and that the layerspacing for graphite increased from 3.35A. to 7.60A.

EXAMPLE 3

To a 125 cc flask was added 10.00 grams graphite and 7.40 grams SbF₅under a nitrogen atmosphere. Ten percent fluorine/nitrogen mixture waspassed through the flask at 54 cc/minute. After stirring for 10 minutesthe product became free flowing and had a lustrous blue-blackappearance. Upon exposure of the intercalate to air, no fuming occurred.The density of the product was 0.833 g/cc compared to 0.845 g/cc for thestarting graphite. Elemental analysis showed the mole ratio of F to Sbto be 4.97, in close agreement to the theoretical ratio of 5.00.

EXAMPLE 4

This example was carried out in the absence of fluorine and serves toshow the advantage of the presence of this gas. To a 125 cc flask wasadded 10.57 grams graphite and 7.82 grams SbF₅ under a nitrogenatmosphere. After stirring for 19 hours the SbF₅ had not completelyintercalated as evidenced by copious fuming of the product upon exposureto air. The product was free flowing and had a dull black appearance.The density of the product was 0.877 g/cc compared to 0.845 g/cc for thestarting graphite.

The above two examples illustrate the improvement to be obtained byusing fluorine as a catalyst for the intercalation of SbF₅ in graphite.In contrast to the previously employed technique, the intercalation timeis reduced from more than one day to 30 minutes or less at roomtemperature and the temperature of intercalation is reduced from 110°Cto room temperature.

EXAMPLE 5

To a 125cc flask was added 50cc tetrahydrofuran and PF₅ /graphite(1.00g, 2.09 meq) intercalate prepared as in Example 2. The mixture wasmaintained at room temperature under nitrogen and was stirred. After onehour the mixture was difficult to stir. Upon standing overnight thetetrahydrofuran polymerized to a rigid glass.

EXAMPLE 6

Propylene was passed at 76 cc/min into a reactor containing 30 ccbenzene and 1.00 gram BF₃ /graphite (2.26 meq BF₃) intercalate, preparedas in Example 1. The reactor was fitted with a condenser and maintainedat 70°C. The appearance of isopropylbenzene product was followed by gaschromatography. After two hours one mole isopropylbenzene/mole BF₃ hadformed.

EXAMPLE 7

In a qualitative test isopropylchloride was observed to alkylate benzeneat 70°C over the BF₃ /graphite intercalate prepared as in Example 1. Theisopropylbenzene product was observed by gas chromatography.

EXAMPLE 8

To a 200 cc flask was added 70.0 cc n-hexane containing 2.32 gramdissolved isobutene. The flask was swept out with dry nitrogen, placedin a bath thermostatted at 20°C and stirred. After 10 minutes the BF₃/graphite (2.00 g, 6.26 meq BF₃) intercalate prepared as in Example 1was added. The ensuing rapid reaction was followed by gaschromatography. After 5 minutes, 98 percent of the isobutene had beenconverted to oligomers. Over the next seven hours small changes occurredin the oligomer distribution. The following table summarizes theoligomer distribution at two specified times.

    __________________________________________________________________________    Oligomer Distribution (%)                                                     __________________________________________________________________________         Iso-                                                                     Reac-                                                                              butene                                                                   tion Conver-      Tetra-                                                                            Penta-                                                                            Hexa-                                                                             Hepta-                                                                            Octa-                                       Time sion %                                                                             Dimer                                                                             Trimer                                                                            mer mer mer mer mer                                         __________________________________________________________________________    15 min                                                                             98   7.9 37.3                                                                              26.3                                                                              14.7                                                                              9.0 4.7 0.0                                          7 hrs                                                                             99   5.7 42.4                                                                              21.4                                                                              11.0                                                                              7.7 3.3 8.4                                         __________________________________________________________________________

The gas chromatograph also showed a small broad peak corresponding tononamer. The oligomer groups were well separated and resolved intoisomeric components. Further addition of 5.98 grams isobutene to thereaction mixture resulted in rapid conversion to oligomers having asimilar distribution.

EXAMPLE 9

To a 200 cc flask was added 70.0 cc n-hexane containing 2.32 gramsdissolved isobutene. The flask was swept out with dry nitrogen, placedin a bath thermostatted at 20°C and stirred. After 10 minutes the PF₅/graphite (3.00 g, 6.27 meq PF₅) intercalate pepared as in Example 2 wasadded. The ensuing reaction was rapid and was followed by gaschromatography. The following table summarizes the oligomer distributionat two specified times:

    Oligomer Distribution (%)                                                     __________________________________________________________________________         Iso-                                                                     Reac-                                                                              butene                                                                   tion Conver-      Tetra-                                                                            Penta-                                                                            Hexa-                                                                             Hepta-                                                                            Octa-                                       Time sion %                                                                             Dimer                                                                             Trimer                                                                            mer mer mer mer mer                                         __________________________________________________________________________    15 min                                                                             45   21.7                                                                              28.3                                                                              21.1                                                                              14.2                                                                              8.7 6.0 Trace                                        7 hrs                                                                             97   26.2                                                                              35.5                                                                              19.7                                                                              10.7                                                                              6.6 1.5 Trace                                       __________________________________________________________________________

It is to be noted that the present dimer for the PF₅ /graphite catalyzedreaction is considerably higher than that obtained from the BF₃/graphite reaction.

EXAMPLE 10

To a 200 cc flask was added 70.0 cc benzene and 3.15 grams (0.0414 mole)of t-butyl fluoride. The flask was swept out with dry nitrogen, placedin a bath thermostatted at 20°C and stirred. After 10 minutes the BF₃/graphite (2.00g 6.26 meq BF₃) intercalate, prepared as in Example 1,was added. A rapid reaction ensued and was monitored by gaschromatography. After 5 minutes the t-butyl fluoride peak haddisappeared indicating 100 percent conversion to products. The productdistribution is summarized in the following table:

    Reaction                                                                             t-Butyl Fluoride                                                                        t-Butyl-                                                                            1,3-Di-t-                                                                             1,4-Di-t-                                      Time (min)                                                                           Conversion (%)                                                                          benzene                                                                             butylbenzene                                                                          butylbenzene                                   __________________________________________________________________________     5     100       73.6  3.7     22.7                                           60     100       74.0  3.7     22.3                                           __________________________________________________________________________

EXAMPLE 11

To a 200 cc flask was added 70.0 cc benzene and 3.15 grams (0.0414 mole)t-butyl fluoride. The flask was swept with dry nitrogen, placed in abath thermostatted at 20°C, and stirred. After 10 minutes the PF₅/graphite (3.00g, 6.27 meq PF₅) intercalate, prepared as in Example 2,was added. This alkylation took place more slowly than the BF₃ /graphitecatalyzed alkylation. Gas chromatographic analysis indicated a 54percent conversion at one hour reaction time to a product comprising70.4 percent t-butylbenzene, 1.9 percent 1,3-di-t-butylbenzene, and 27.8percent 1,4-di-t-butylbenzene.

EXAMPLE 12

To a reactor maintained under nitrogen was added 99.5% n-hexane (6.0cc,4.0g), BF₃ /graphite (1.0cc, 0.44g, 1.2 meq BF₃) intercalate prepared asin Example 1 and fluorosulfuric acid (0.68g, 6.80 meq). The reactor wasagitated and maintained at 22°C. Samples were withdrawn periodically foranalysis by gas chromatography. The following table summarizes theproduct distribution after six hours (effective LHSV = 1). The n-hexaneconversion at this point was 6%.

    ______________________________________                                        Product Distribution                                                          ______________________________________                                        Hydrocarbon            Wt. %                                                  ______________________________________                                        Propane                0.8                                                    2-Methylpropane        24.0                                                   Butane                 0.8                                                    2-Methylbutane         25.0                                                   Pentane                0.9                                                    2,2-Dimethylbutane     2.1                                                    2,3-Dimethylbutane and                                                        2-Methylpentane        25.9                                                   3-Methylpentane        8.1                                                    C.sub.7.sup.+          12.4                                                   ______________________________________                                    

The above results illustrate isomerization/disproportionation ofn-hexane over BF₃ /HSO₃ /graphite catalyst.

EXAMPLE 13

This example illustrates that in contrast to fluorine, chlorine failedto catalyze the intercalation of BF₃ in graphite.

Boron trifluoride and 10 volume percent chlorine in nitrogen werecostreamed each at 40 cc/min through a 15.00 g bed of graphite at 22°C.No temperature change was observed in the bed. After 3 hours contacttime no intercalation had occurred as evidenced by no increase in weightof the graphite.

When BF₃, PF₅ or 10 volume percent fluorine in nitrogen wereindividually streamed through a bed of graphite (20-65 mesh), nointercalation occurred as indicated by no increase in weight of thegraphite. The following table summarizes the data:

    ______________________________________                                                          Contact        Wt. of                                               Flow Rate Time     Temp. Graphite                                                                             Weight                                Reactant                                                                              (cc/min.) (min.)   °C                                                                           (grams)                                                                              Increase                              ______________________________________                                        BF.sub.3                                                                              40         90      22    10     None                                  PF.sub.5                                                                              40        100      24    20     None                                  10% F/N.sub.2                                                                         40        255      24    20     None                                  ______________________________________                                    

It is to be understood that the foregoing description is merelyillustrative of preferred embodiments of the invention of which manyvariations may be made by those skilled in the art within the scope ofthe following claims without departing from the spirit thereof.

I claim:
 1. A method of intercalating a Lewis acid fluoride in graphitewhich comprises contacting graphite with a Lewis acid fluoride, having aboiling point below about 300°C., of an element of Group II, IIIA, IV, Vor VIB of the Periodic Table in the presence of fluorine at atemperature within the approximate range of 15° to 150°C for at least aperiod of time to effect a weight increase in the graphite, the relativeamount of said Lewis acid fluoride and fluorine being between about 30to 1 and about 2 to 1 on a weight basis.
 2. The method of claim 1wherein the temperature is between about 20°C and about 40°C.
 3. Themethod of claim 1 wherein the Lewis acid fluoride is boron trifluoride.4. The method of claim 1 wherein the Lewis acid fluoride is phosphoruspentafluoride.
 5. The method of claim 1 wherein the Lewis acid fluorideis antimony pentafluoride.
 6. The method of claim 1 wherein said periodof time is between about 1/4 and about 24 hours.
 7. The method of claim1 wherein said period of time is between about 1 and about 10 hours. 8.The method of claim 1 wherein the fluorine is diluted with an inert gassuch that the fluorine content of the diluted mixture is between about 1and about 50 volume percent.
 9. A composition consisting essentially ofgraphite having intercalated in the lattice thereof between about 5 andabout 50 weight percent of boron trifluoride.
 10. A compositionconsisting essentially of graphite having intercalated in the latticethereof between about 5 and about 50 weight percent of phosphoruspentafluoride.
 11. The composition of claim 9 wherein the intercalatedamount of boron trifluoride is between about 10 and about 40 weightpercent.
 12. The composition of claim 10 wherein the intercalated amountof phosphorus pentafluoride is between about 10 and about 40.